Death in nature has no purpose – only consequences

Alexander Panchin on biological immortality

Inna Herman, "Theories and Practices" talked– For what purpose did nature intend to destroy each of the creatures she created?

– It is wrong to assume that nature has some purpose. Why do hydrogen and oxygen molecules combine with each other? Because they have a goal to create a water molecule? No, it's just that these are the laws of physics, these are the properties of these molecules. So death is a property of the living and in general has no purpose, only consequences.

– What is the biological function of death?

– The question implies that death has a function. This is not quite true: death does not necessarily have any function. Sometimes death is simply the result of the accumulation of damage incompatible with life. But in some cases, the presence of a planned death can give an evolutionary advantage: in such cases, we can talk about its evolutionary function. Some insects, spiders, mollusks, fish carry out only one reproductive act in their lives. Soon after the reproductive act, they die. The fact is that maintaining the vital activity of a parent requires energy and resources. Energy that can be invested in increasing the size of the brood. It turns out that if survival after the act of reproduction costs the body at least a few descendants, and the chances of surviving to the next reproductive act of the descendants are similar to such chances of the parent, then the survival of the parent does not contribute to the growth of the population. Natural selection does not preserve the ability of such a species to live long after the reproductive act. Of course, such a strategy is found in species that do not care about offspring, which, as a rule, are independent immediately after birth.

In humans, offspring will not survive without the care of adult parents, we can give offspring many times, we have a different breeding strategy, we live significantly longer. Moreover, due to the presence of our culture, life experience and the preservation of the ability to transmit it acquire value. In this regard, we are helped by the survival of elderly experienced people with a lot of knowledge, able to teach young children and take care of them. Therefore, our desire to increase life expectancy may be quite biologically and evolutionarily justified.

However, there is a hypothesis that the death and aging of people may be to some extent programmed at the level of genes. Several facts indirectly support this hypothesis. Firstly, there are works in which some genetic features of "super-long-livers" have been found. In addition, some model animals for the study of aging (mice, roundworms) with the help of certain mutations managed to significantly prolong life. We know for sure that there are mechanisms of programmed cell death. If a human cell accumulates a lot of damage, it ends up committing suicide through a process called apoptosis. This mechanism is very important, as it protects us from the occurrence of cancer – a disease associated with the fact that the damaged cells of the body begin to divide uncontrollably. Today, there is an active search for a hypothetical "genetic program of death" in humans and ways to cancel it, but at this stage it is difficult for me to speculate what achievements we will achieve in this area.

– What are the forms of immortality in nature? And with what degree of conditionality can we talk about it at all?

– Sometimes they talk about immortal cell lines. These may be special animal cells or populations (clones) of bacteria. The cells divide, and it would seem that each of the new cells continues the life of the old one. Thus, each cell is essentially a continuation of the very first cell. There are several problems with this notion of immortality. Firstly, some studies show that cell division does not always occur evenly, that sometimes it is possible to distinguish between an "old" and a "new" cell, and the "old" cell has less potential for reproduction and less chance of survival. Secondly, the cells obtained as a result of division differ from the original one, accumulate new mutations. Therefore, after each division, we do not get exactly the same cell that we dealt with before. It is clear that such immortality is rather conditional.

Another example of conditional – I would even say, "potential" – immortality can be found in freshwater hydra. If you cut off a large enough piece of hydra, then it will have the ability to develop into a new hydra. Theoretically, in this way, hydra could exist indifferently for a long time, but in practice we do not know how long this can happen.

There is another interesting example. There is a species of conditionally immortal jellyfish Turritopsis nutricula, which belongs to the class of hydroids. In hydroids, the life cycle, as a rule, looks like this: their larva – a planula – attaches to the substrate, forming a polyp. The polyp grows, forming a colony of polyps, from which jellyfish can bud off. This is a type of asexual reproduction. Jellyfish have gonads and can produce male and female type germ cells. The germ cells of the two types merge to form a zygote, from which a planula larva is subsequently formed and the cycle repeats. Turritopsis nutricula has the ability to turn back into a polyp. Thus, they have a "theoretical immortality". But how long such organisms can live, whether they are immortal in practice, is unknown. In the wild, the risk of being eaten is high, and even an immortal organism will not live forever.

– Can cloning be considered immortality?

– First of all, I would like to note that, although no one has tried to clone a human yet, cloning of other animals has been done many times. All the fundamental technologies for this process have been developed for a long time. With human cloning, the question is no longer so much for the scientific component (although time will be needed here), as for the ethical one.

There is a common misconception, partly inspired by Hollywood cinema, that human cloning is when they take a person, launch him into some magic box, and at the exit they get an identical copy with the same memories, personality. In fact, when cloning animals, an egg is taken, a nucleus is embedded in it from the cell of the cloned adult animal, and then the development of this egg is started. If we clone a person, then we will need a surrogate mother who carries a fetus for nine months, will give birth to a child. This child will be genetically identical to his older clone in many physical characteristics, but he will represent a completely new person, a completely new personality. Thus, modern cloning of an entire organism can hardly be considered a path to immortality. There are, however, serious hopes that cloning of individual organs will significantly increase life expectancy in the future. Imagine if we could replace the old heart or liver with a completely new organ – the same as it was in his youth.

– Can the transfer of information from the human brain to electronic media be considered immortality?

– It is not completely clear exactly how information is stored in our brain and whether it can be completely transferred to an electronic medium. But I would consider an even more radical example. Imagine that we have created such a machine that can scan a person to the atom and recreate an absolutely exact copy, which will preserve all the memory, all the thoughts that were in a person's head at the time of scanning, all the skills, all the bad habits. Here you are standing, and your absolute copy is standing in front of you. For everyone around you, this copy is indistinguishable from you. If you are destroyed and a copy is released, no one will ever notice it. But will you now agree to be destroyed and a copy left?

On the other hand, we could take turns replacing every atom in our body with the same atom, and no one, including ourselves, would notice the difference. Our body is constantly undergoing changes, we are growing up, some of our cells are dying, new ones are appearing, but it seems to us that it is still us. Where is the boundary that allows you to say whether this is the same person or already another? I can't answer that question.

But for others, such an opportunity would be wonderful. Imagine if they could immortalize Einstein like that. Then he would now be able to lecture us on physics and help promote scientific and technological progress.

– Will the decoding of DNA, which allows to restore the cell structure in identity, lead to immortality?

– Today, technologies allow you to fully read your own genome for a relatively small fee – that is, each nucleotide of those DNA sequences that determine the structure of our body. This will be a file weighing about 3 gigabytes, which can be placed on a USB flash drive, which in turn can be hung around your neck under the guise of a souvenir (which I recommend to wealthy citizens who do not know where to put a couple of extra thousand dollars). The work of the famous biologist Craig Venter has shown that we can synthesize an artificial DNA sequence, embed it into a cell, and the cell will "work". At the moment, this has already been done with a small bacterial chromosome. Theoretically, if you read the entire human genome, in the future it will be possible to synthesize each of its chromosomes, insert them into the nucleus of an egg, grow a clone. We will be able to make an immortal "mock-up of a person" with a certain set of properties, eye color, hair. But I'm not sure that this is the path to immortality. Rather, the path to asexual reproduction.

By the way, I must say that cloning has certain limitations. During human development, not only his genetic material plays a role, but also the conditions of his intrauterine development. In addition, the development of some traits is not strictly determined by genes, but is subject to stochastic influences. For example, the inheritance of the right position of the heart in humans is very interesting. It turns out that there is a mutation that leads not directly to the right position of the heart, but to the inability of the developing organism to distinguish right and left when choosing the position of the heart, that is, people with such a mutation are likely to have a heart on the right, and with some on the left, where it should be. There are other examples of such "inheritance of randomness". That is, it is not a fact that the clone will be biologically identical to the original.

Portal "Eternal youth" http://vechnayamolodost.ru11.03.2013